Bridge and mobile launching structure therefor



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BRIDGE AND MOBILE LAUNCHING STRUCTURE THEREFOR Filed June 12, 1945 16 Sheets-Sheet l6 a 3 "F; a v

Suva rot LesZeT' P. F fos$ Patented June 12, 1951 BRIDGE AND MOBILE LAUNCHING STRUC- TUB/E THEREFOR Lester P. Frost, United States Army, Fort Belvoir, Va.

Application June 12, 1945, Serial No. 599,040

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 16 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment to me of any royalty thereon.

This invention relates to bridges, particularly mobile bridges having pivotally connected sections, and means operably rotating the respective sections around the respective pivot point to launch and retrieve the bridge.

It is an object of this invention to provide a bridge carried by a vehicle possessing means for rapidly launching and retrieving the bridge with a minimum crew.

It is another object of this invention to provide a scissor or jack-knife-type bridge construction transported by a trailer containing actuatingmechanism for launching the bridge across an open span in the terrain.

Another object of this invention is to provide a bridge of the class herein described mounted on a trailer provided with rear steering means to aid in transversing narrow winding road and sharp curves.

Another object of this invention is to provide a bridge of the class herein described having extensible floor beams.

.Another object of this invention is to provide a bridge of the class herein described folded upon a trailer, pivoted to the rear thereof for launching, and counterbalanced with a prime mover coupled to the trailer.

Still another object of this invention is to provide a scissor-type bridge with one section thereof pivoted to a trailer containing hoist means raising the bridge from the trailer body and swinging the bridge around its pivot to a point slightly beyond vertical.

A further object of this invention is to provide means for opening the far section of a scissor type bridge independently of the means for lowering the near section of the bridge. 7

A further object of this invention is to provide reversible opening and lowering means for a scissor-type bridge so that the opening and lowering means may function as closing and raising means.

A further object of this invention is to provide a bridge of the class herein described removably pivoted to a transporting vehicle.

A further object of this invention is to provide a bridge of the class herein described mounted on a trailer releasably coupled to a prime mover whereby said trailer may be employed as an approach ramp to the bridge.

A still further object of this invention is to provide a bridge of the class herein described comprising two like sections pivotally secured together whereby the bridge may be launched and retrieved from either end.

It is also an object of this invention to provide a bridge of the class described pivotally secured to any launching structure.

It is a further object of this invention to provide a bridge of the class herein described comprising av multiplicity of interchangeable parts which may be transported individually or collectively and assembled rapidly and easily at any desired location.

. The foregoing and other objects of this invention will be more apparent from reading the specification in conjunction with the drawings, forming a part thereof, wherein:

Fig. l is a perspective view of the bridge in folded condition upon the transporting trailer with the prime mover attached thereto;

Fig. 2 is a perspective view of the bridge in partially launched position with the opening.

cable contacting the boom sheaves;

Fig. 3 is a perspective view of the bridge in partially retrieved position with the openingcable out of contact with the boom sheaves;

Fig. 4 is a perspective diagrammatic view of the bridge and launching operating mechanisms;

Fig. 5 is a perspective view of a bridge section, parts removed;

Fig. 6 is a detailed section taken on line 6-6 of Fig. 5;

Fig. 7 is a detailed horizontal section showing the connection of the floor beams to the girders;

'Fig. 8 is a perspective view of the parts shown in Fig. '7 in a partially disassembled condition;

Fig. 9 is a detailed section taken on line 9-9 of Fig. 5, parts added;

Fig. 10 is a horizontal section on line Ill-l0 of Fig. 9, parts shown in elevation;

Fig. 11 is a detailed vertical section taken on line Hll of Fig. 9;

Fig. 12 is a detailed section of the gear-box and connection to the floor beam;

Fig. 13 is a top plan view of the bridge hinge section with the bridge fully extended;

Fig. 14 is a side elevation of the bridge hinge section with the bridge fully extended;

Fig. 15 is a vertical section taken on line of Fig. 14;

Fig. 16 is a horizontal section taken on line l6l6 ofFig. 14;

Fig. 1'7 is a horizontal section taken on line -51 of Fig. 14;

Fig. 18 is a detailed vertical section taken on line I 8I B of Fig. 5, with parts added to complete the structure;

Fig. 19 is a detail horizontal section taken on line I9l9 of Fig. 18;

Fig. 20 is a side elevation of the approach end of a bridge section;

Fig. 21 is a perspective view of the approach end of a bridge section;

Fig. 22 is a horizontal section taken on line 22-22 of Fig. 20;

Fig. 23 is a vertical section taken online '23-'23 of Fig. 22;

Fig. 24 is a vertical section taken on line "EL-2'4 of Fig. 22;

Fig. 25 is a detail vertical section taken on line 2525 of Fig. 23;

Fig. 26 is a perspective view of the pivotal connection between the bridge and trailer with the pivotal relationship secured;

Fig. 27 is a perspective view of the pivotal connection between the bridge and trailer with the pivotal relationship released;

Fig. 28 is a top plan view of the front half ,of the trailer showing the relationship between the component launching parts;

Fig. 28a is a top plan view of the rear half of the trailer showing the relationship between the component launching parts;

Fig. 29 is a side elevation of the structure shown in Fig. 28;

Fig. 29a is a side elevation of the structure shown in Fig. 28a;

Fig. 30 is a plan view of the hydraulic launching system;

Fig. 31 is a side elevation of the structure shown in Fig. 30, parts omitted to illustrate more clearly the hydraulic hoist connections;

Fig. 32 is a side elevation of the structure shown in Fig. 30, parts omitted to show more clearly the connections of the hydraulic ram;

Fig. 33 is a side elevation of the structure shown in Fig. 30, parts omitted to show more clearly the connection between the hydraulic reservoir and the suction side of the hydraulic pump;

Fig. 34 is a perspective view of the control panel as seen from the left side of the operators platform;

Fig. :35 is a perspective view of the control panel from the center of the operators platform;

Fig. 36 is a side elevation of the control parts shown in section;

Fig. 37 is a rear elevation of the control panel, parts shown in section;

Fig. 38 is a top plan view of a portion of the rear of the trailer showing the relationship be tween the bridge opening cable and guiding sheaves;

Fig. 39 is a vertical section taken on line 39 39 of Fig. 38;

Fig. 40 is a horizontal section of the swivel sheave taken on line 49-49 of Fig. 39; and

Fig. 41 is a perspective view of the trailer-prime mover counterbalance couple.

In the drawings wherein like members are given the same reference numeral, the invention comprises, generally, a bridge 3, Figs. 1 and 2, pivotally mounted to a mobile vehicle 2, it being clearly understood, of course, that the bridge may be utilized on permanently placed launching structures as well as mobile structures. The mobile vehicle may be any powered vehicle, but preferaly it is a prime mover I having a trailer 2 secured thereto, as it is contemplated within the invention to utilize the trailer as an approach ramp to the bridge 3 when the trailer is disconpanel,

nected from the prime mover I. The bridge 3 may be viewed generally as any bridge, such as a girder or truss-type bridge, divided and pivoted together at the middle; preferably, however, the bridge, is formed of two longitudinally extending half sections. For the purposes of illustration and description, the section pivotally secured to the trailer or other launching emplacement is designated as the near section 5, Whereas the freely swinging section is designated the far section 6. These two half sections are, preferably, identical in construction and have interengaging brackets I and 8 pivotally connected by a pin :9, Figs. 14 and 18, inserted therethrough at .a point beneath the lower surface of the bridge to provide a scissor-type, substantially symmetrical bridge. The near section of the bridge 5 is releasably pivoted to the rear portion of the trailer frame; thus the bridge may be folded upon the trailer for transporting. Hoist means I ll, Figs. 2 and 3, are provided on the trailer for raising the bridge in a folded condition to a point where the center of gravity of the bridge is beyond the trailer-to-bridge pivot point. Separate means are provided for holding and lowering the near section of the bridge and for opening the far section of the bridge to form a continuous bridge surface.

As previously stated, any conventional bridge structure may be used in practicing this invention. It has been found to be advisable, however, to employ a modified through-girder type bridge, preferably constructed of aluminum. This is the type construction illustrated in the drawings and described hereinafter. For spanning relative long distance, such as to feet, it has been found desirable to construct the component parts of the bridge with aluminum in or der to obtain a high strength-weight ratio. Since each of the two sections of this new girder bridge is identical, the specific details of construction will be described for only one section.

The principal support of the bridge load is provided by two girders II, Figs. '5 and 8, each of which comprises top and bottom flanges I2, Web sheet or sheets I4, positioned in the flanges I2, and stiffeners I5 spaced along and connected with the top and bottom flanges I2 of each girder II. Preferably, the stiffeners I5 are angle members arranged in parallel pairs, one on each side of the web I4. When the stiifeners I5 extend between the extending flanges I 2a of the top and bottom flanges l2, suitable filler plates or spacers I6 are positioned intermediate the stiffeners I5 and the web I l. Cover plates I? may be placed on either or both of the top and bottom flanges I2 if desired.

Connecting the girders are transverse floor beams I8, preferably formed of I-beams having portions of the flanges cut out on one side of the I-beam web and positioned in a manner such that the web I8a of the I-beam contacts the extending leg I5a of the inside stiffener I5 and is fastened thereto. The other side of the I-beam web I8a is fastened to the Web I4 of the girder II by an angle member I9 secured thereto. In order that the bridge may be transported in a minimum space and extended after launching, the floor beams are formed of two half sections 20 and 2 I, Figs. 9 to 12, inclusive, each secured to a separate girder. Channel members 22 are positioned on each side of the floor beams and rigidly secured to one section 20 thereof. These channel members 22 extend along the other section 2I which has a longitudinal slot 23 therein, adapted to receive a bolt 24 inserted therethrough and extending through aligned apertures 26 provided in the channel members 22. The bolt is retained in the channel members 22 by the head 24a of the bolt 24 which contacts the outer surface of one channel member 22 and a nut 25 engaging the bolt which contacts the outer surface of the other channel member 22. Interposed between the flanges of the slotted floor beam section 2| and the channel members 22 extending there-along are bearing. slides 21 secured to the I-beams. These slides 21 are preferably chamfered at the ends in a conventional manner for bearing slides.

To separate the floor beam sections thereby increasing the length of the floor beam and hence the width of the bridge, a gear box 28 is secured to the slotted beam section 2| and operates a screw shaft 29 terminally secured to one of the channel members 22 in any suitable manner such as an angle bracket 30. The gear box 28 is adapted for manual operation by turning a substantially T-shaped crank having a polygonal socket (not shown) engaginga polygonal-headed shaft 3I having a pinion gear 32 positioned thereon intermeshing with a gear 33 positioned on and operably engaging the screw shaft 29. It is not necessary to provide gear boxes on each floor beam, two for each bridge section measuring forty feet has proved to be adequate.

A series of stringer assemblies are provided to span the gap between adjacent floor beam sections 20 and 20, or 2I and 2I, respectively. Each of these stringer assemblies comprises longitudinal stringers and transverse beams. One of the longitudinal stringers, called the curb-supporting stringer 34 for the purposes of description, is in the form of a channel member having a section cut out of the lower edge of each end so that the channel member may be extended over and to the midpoint of the floor beam I 8 and support a curb member 35 bolted thereon. The curb members are provided with flanged ends 35a for bolting each curb section to the adjacent curb section through a curb divider 36 positioned between adjacent curb sections and secured to the stiffeners I5 and floor beam I8. The other longitudinal stringer 31 is in the form of a channel member positioned near midpoint of the floor beam I8 and between adjacent similar floor beam sections in a manner such that its top surface is in the same plane as the top surface of the floor beam I8. The transverse beams 38 are preferably a pluralit of I-beams positioned intermediate the longitudinal stringers 34 and 3'1 and have their top surfaces in the plane of the top surface of the floor beams I8. The transverse beams 38, Figs. 3, 18 and 19, are secured to the longitudinal stringers 34 and 31 in any suitable manner, such as welding and riveting. If it is desired, however, to retain the bridge in a condition for rapidly disassembling, angle members 39 may be bolted to the longitudinal stringers 34 and 31 and transverse beams 38 to provide a connecting link between the two parts. Likewise, angle members 40, Figs. 8, 9 and 11, may be employed as the connecting link between the top of the floor beam I8 and the curb-supporting stringer 34. An angle member 4|, Figs, 22 to 24, inclusive, may be employed as the connecting link between the longitudinal stringer 3'1 and the channel member 22 rigidly secured to the floor beam section 20; and, an angle member 42 may be employed to connect the longitudinal stringer 3'! to a saddle bracket 44 positioned interme- ,to the bridge center.

diate the bearing slide 21 and the top flange of the slotted floor beam section 2I. Lift brackets 45 and 45a, Fig. 5, in the form of spaced members 46 supporting a pin 4! therebetween are positioned in the bridge, preferably between the pivot end floor beam I8 and adjacent transverse beams 38 and between the approach end floor beam I8 and the adjacent transverse beams 38, respectively. These lift brackets 45 and 45a are designed to engage operably the hooks provided on the lifting cables 50, Figs. 2 and 3.

Diagonal sway braces 5I, Fig. 5, are positioned between the longitudinal stringers. These sway braces. 5I are connected in any suitable manner, preferably through angle members 52, to the longitudinal stringers 34 and 31 respectively. The sway braces 5I are positioned in a manner such that they are beneath the transverse beams 38 and in contact therewith so that they may be secured thereto. Since each bridge section may be viewed as two longitudinal half sections due to the extensibility of the floor beams I3, the sway braces 5I are positioned to effect a triangular support arrangement in each longitudinal half section to increase rigidity of the bridge structure.

The two ends of the bridge section may be appropriately termed the approach end, meaning that end from which one approaches the bridge, and the pivot end, designating that end of the bridge section pivotally secured to the other bridge section. The pivot end of each bridge section is provided with bracket plates secured to each side of the grider web which extend outwardly and downwardly therefrom. The bracket I, Figs. 1, 14, 15 and 17, comprises plates secured to one of the girders and flared outwardly at the extending end so as to increase the space therebetween; whereas the bracket 8 comprises plates secured to the other girder and unflared. Since each of the bridge sections is identical in construction, the flared bracket plates I on one section receive the unflared bracket plates 8 of the other bridge section. These bracket plates are provided with apertures 4 adapted to align and receive a pivot pin or shaft 9 inserted there through. The design of the brackets and position of the apertures 4 are such that when pivoted together, the pivot point of the bridge is spaced from and slightly below the bridge structure so as to provide a clearance between the respective members of the bridge section during pivotal operation. A portion of the lower or bottom girder flanges must be cut out to afford clearance for the downwardly extending portion of the bracket plates 1 and 8. This necessitates the pivot end floor beam I8 being suspended slightly difierent- 1y from the others hereinbefore described. This beam is supported by angle members 53 and 53a, Figs. 18 and 19, secured on each side of the beam web lBa, one of which angle members 53a is secured to the pivot bracket plate '5 or 8 and the other of which angle members 53 is secured to the girder web I4. An additional support is pro- Vided in the form of a triangular support plate 5'5 having a flanged side portion 53 secured to the floor beam web I8a and another side secured to the extending leg of an angle member 51 secured to the girder. Likewise, the curb-supporting stringer 34 extends beyond the floor beam I8 Hence, the curb divider 36, Figs. 5 to 8, inclusive, positioned on this beam I8 is smaller than the others so that it may fit inside the curb-supporting stringer 34 and curb member 35 when the extending flanges of these members are recessed to receive the divider 36. The top portion of the girder web has secured to each side spacer plates 69, Figs. 14 to 16, inclusive, supporting bracket plates 6! having outward and downward projections 62 and 63, respectively, and portions of the bridge web contained between the bracket plates BI are cut out to effect a recess 64 into which is positioned a sheave 65 supported by a pin 55 inserted through the plates Bl.

The downwardly extending projections 63 on the two bridge sections are in contact when the bridge is fully extended. An angle member 61 is positioned over the top and bottom bracket plates 6i and l and 3 respectively, and angle members 61a are positioned intermediate the two bracket plates. Suitable filler plates l6, Fig. 5, are positioned between the girder web it and angle member 6'1 and (57a, Figs. 13 and 14:. On top of the girder H and just back of the sheave 65 is a channel member 68 supporting a pin (59 and adapted to engage an eyelet or hook 49 secured to the bridge opening and closing cable H3. These pins 69 when not engaging the opening and closing cable iii serve as guides for said cable and it is therefore advisable to position a small sheave on the pin 69 to decrease the wear on the cable. Appropriate guide members ll may be positioned on the face of the girders if desired.

The approach end of the bridge has a portion of the girder web 54 extended upwardly, and plates 74, Figs. 23 and 24., securely fastened to each side thereof. These plates i4 extend upwardly defining a channel 15, Figs. 20 and 21, therebetween in the lower portion where the girder web i4 is removed. Rigidly secured to the upwardly extending plates is a pivot member 18, Figs. 20 to 23, inclusive, having a lipped groove provided therein and adapted to receive a pin member 294 on the trailer 2 to effect a releasable pivot connection between the bridge and trailer, as will be discussed more fully hereinafter. This pivot member 16 may be described as a single unit, since it may be easily constructed as a single unit, in the form of a block member having a portion thereof cut out to form a flared groove Tl substantially parallel to the bridge deck surface, and an arcuate aperture l extending upwardly of said groove effecting a lip 19 on the upper portion thereof. The lower portion of the pivot member is channeled to receive a safety stop 86 pivotally mounted therein and adapted to restrict or open selectively the groove 71 whereby the pivot pin I94, Figs. 26 and 27, may be retained in the arcuate aperture 16 or removed therefrom. Since this end of the bridge bears the total weight of the bridge during launching and it is also contemplated to launch another bridge from this bridge section, it is desirable to reinforce this end of the bridge. A divided floating beam 81, Figs. 22, 24 and 25, is connected, therefore, to the bridge structure and spaced from the main floor beam iii of the approach end of the bridge. These two beams 85 and i8 are covered on the under surface with a divided bearing plate 82 to provide a bearing surface with sufiicient area to support the bridge on any type terrain, as well as providing easy extensibility of the bridge. Positioned on top of the girder near the pivot member is a bracket 83, Figs. 20 and 21, similar to the cable engaging bracket on the pivot end. The bracket 83 serves as a cable guide when the bridge is near extended position, and as a yoke bracket for tying two bridges together. Positioned outside the girder is a bracket 84 adapted to receive a yoke employ d n se u g two such bridge t ethe The deck surface 85 of the bridge may be of any suitable material such as wooden planks or aluminum grill work. The deck plate members are preferably formed in units adapted to cover the space between adjacent floor beam sections 20 and 2B or 2! and 21, respectively, Fig. 9, and have the width of substantially half the bridge. These deck plate units may be secured to the bridge with angle members 86, Fig. 6, extending downwardly therefrom and positioned to centact angle members 86a. extending from the longitudinal stringers 34 and 31, Figs. 5, 6 and 1 1, each of said angle members being apertured to receive a, bolt and nut assembly 81 when aligned.

Eyelets 88 are secured to the main floor beam at the approach end of the bridge and receive studs extending downward from portable approach ramps employed when the trailer is disconnected from the bridge.

As previously stated, any mobile vehicle may i be employed to transport and launch this bridge,

or the bridge may be used on permanently emplaced launching structures. Since mobility is a desirable feature of this bridge structure, and it is contemplated employing the transporting vehicle as an approach ramp, a trailer. 2 of the general semi-trailer design has been found to be the most appropriate and desirable transporting vehicle and launching structure. The trailer has a suitable number of longitudinal supports 90, Fig. 23, preferably in the form of I-beams or girders, which are connected by suitably positioned transverse beams 9 I. The webs of the longitudinal and transverse beams are provided with suitable apertures to permit movement of the necessary parts therethrough.

The trailer is supported in operable position at the front by a conventional fifth wheel arrangement 92, Fig. 1, connecting the trailer '2 to the prime mover I. Hydraulic or mechanical jacks 2), Figs. 28 and 29, are provided to support the front of the trailer when the prime mover is disconnected. At the rear, the trailer is connected to an axle 9%, Fig. 28a, having pivotally mounted thereon spindle arms terminating in spindles 96 provided with wheels 91. The spindle arms 95 are connected with a tie rod 98 and hydraulic cylinders 99 which simultaneously pivot the spindles 96 around their pivotv points 100 to facilitate transversing narrow, winding roads and sharp curves. Securely fastened to the tie rod 98 connecting the spindle arms 95 is a yoke or bracket member [0| terminating in end sections 102 freely movable across a plate I03 secured to the axle 94. Apertures M34 are provided in the ends I02 of the bracket member l0! and in the plate I03 which are adapted to receive a retaining pin I05 when the apertures Hi l are aligned to lock the tie rod es in a position such that the spindle 96 connected thereto are locked in alignment with the axle 94.

Suitably mounted below the deck of the trailer by appropriate brackets, hanger straps and the like, all well known in the art, are the bridge operating mechanisms which include a power plant, hydrosteer mechanisms, and a control panel forming part of the deck and adapted to be pivoted to a vertical position for operation. The power plant may be of any desired type and of conventional design, but the preferred power plant is a constant speed internal combustion engine 110, Figs. 28 and 29. A fuel tank III for the engine is likewise mounted in the trailer body 

